The Chargers should have their No. 1 running back this weekend. The Steelers probably will not.

The first official injury reports have the week were released Wednesday. While the Chargers finally got RB LaDainian Tomlinson back, a number of other key players — Willie Parker, Marc Bulger, Vince Wilfork and Cedric Benson — were unable to practice.

Chad Pennington, Shawne Merriman and Frank Gore were among the key players who sustained injuries in Week 3.

The San Diego County District Attorney’s Office has decided to not move forward on reality TV star Tila Tequila‘s accusations of domestic violence against San Diego Chargers LB Shawne Merriman.

A day at the San Diego Chargers’ training camp revealed a focused Philip Rivers, an aggressive defense, some impressive rookies on both sides of the ball, and more. Pat Kirwan offers his observations.

Here are some observations from the first weekend of preseason play.

LaDainian Tomlinson is motivated to show he still has what it takes to be an elite running back at the age of 30.

Chargers LB Shawne Merriman reported to training camp Monday, along with quarterbacks, rookies and other players coming off injuries.

The bar has been set with the recent success of the Cowboys, Patriots, Ravens, Chargers and Steelers’ 3-4 defenses, and now it has become vogue to run the scheme. As many as 15 teams are either making the switch or infusing elements of the 3-4 defense, but can they be successful? Here are five key ingredients that will make or break the transition.

I’m glad you enjoy the players-only sessions we have on NFL Network. I enjoy being a part of it. Warren, Deion, Marshall and “Mooch” offer great insight, and I’m just there (LOL). This week’s installment asked this question: “If you had to start a franchise, who would you choose?” Deion chose Mike Tomlin, Warren chose Mario Williams, Marshall chose Shawne Merriman and I chose Michael Vick.

The Chargers expect to have injured LB Shawne Merriman and RB Darren Sproles at offseason workouts this week.

Lost in all of the LaDainian Tomlinson turmoil in San Diego is Shawne Merriman and his rehabilitation from his knee injury. The loss of Merriman had a huge impact on the Chargers’ defense, which registered 42 sacks in 2007 but only 28 in 2008.

Behind the scenes, several Chargers have privately expressed concern over the ongoing LaDainian Tomlinson saga in San Diego.

In the past 20 months, the Chargers have handed out lucrative contract extensions to seven defensive players. Meanwhile, linebacker Shawne Merriman has not gotten anything close to one.

Now Merriman’s future in San Diego is, at best, clouded. Next season, the linebacker will be headed into the last year of his contract.

Chargers LB Shawne Merriman informed the team today that he has decided to have surgery on his knee and will miss the remainder of the 2008 season.